Video conferencing, streaming, and broadcasting generally include digital video transport over a communications channel such as dedicated cable, a wireless connection, or the Internet. Especially for video conferencing, streaming, and broadcasting, video transport systems are configured to provide the transmitted video stream(s) substantially ‘live’ or in real time, without significant interruption of the video stream(s). Video transport systems may be configured to transmit video, audio, and other media (e.g., graphics, data, metadata), and may be referred to as media transport systems.
Communications channels have a limited bandwidth and the bandwidth limit may impact the transmission of video, especially if multiple channels of high quality video are desired. Traditional solutions to manage bandwidth include limiting the number of video streams transmitted and/or limiting the type and/or quality of video streams. Typically bandwidth is restricted by rejecting video streams with too high of a bandwidth demand and/or adjusting the high demand video stream to a lower bandwidth stream. Video parameters such as image resolution (the image height, image width, and number of pixels), frame rate, compression, color depth, and color encoding format, affect the bandwidth demand of a video stream. Lower image resolution, lower frame rate, higher compression, lower color depth, and simpler color encoding (e.g., 4:2:0 Y′:Cb:Cr encoding or grayscale only) may reduce the bandwidth requirements of a video stream. But, reducing bandwidth through these parameters also reduces the quality of the video stream.
Traditionally, a user configures a video transport system for a balance between bandwidth demand and video quality on a per-video-source basis. If the video source changes (presenting different video parameters), the balance may be disturbed and the video transport system may need to be reconfigured. For a dynamic system with variable video sources and/or adept video routing, the user may need to set the video parameters to accommodate the highest demand video stream at the expense of video quality for any other video streams. Setting parameters for the highest demand stream may waste bandwidth for other (potentially less critical) streams. Setting parameters for the lowest demand (or even typical demand) may compromise quality of the higher demand streams. Additionally, users of video transport systems may not recognize the optimal way to preserve video quality while adjusting video parameters for a particular video stream or a range of video stream types.